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http://cimav.repositorioinstitucional.mx/jspui/handle/1004/1375| Synthesis, characterization and photocatalytic evaluation of MWO4 (M = Ni, Co, Cu and Mn) Tungstates | |
| ALEJANDRO LOPEZ ORTIZ VIRGINIA HIDOLINA COLLINS MARTINEZ | |
| Acceso Abierto | |
| Sin Derechos Reservados | |
| H2 generation photocatalysis | |
| Photocatalysis is an technology that can be applied to solve environmental and energy problems such as the production of hydrogen from the dissociation of the water molecule. Tungstates exhibit many potential applications in different areas of technology due their excellent electrical properties. Nanostructured tungstate materials are known for their wide applications in conventional catalysis, as scintillator material, in photoluminescence, optical fibres and as materials in microwave technology. Eventhough these present enough chemical and thermal stability, very scarce reports are found in the literature related to their uses as photocatalysts for hydrogen production through water splitting. The aim of the present study is the synthesis and characterization of family tungstate MWO4 (M = Co, Cu, Mn and Ni) materials through co-precipitation in order to evaluate their photocatalytic activity towards the production of hydrogen within the visible light range. Characterization consisted in XRD, BET, UV-Vis and SEM, while the photocatalytic evaluation was as follows: 200 mg of CuWO4, CoWO4, NiWO4 and MnWO4 powders were individually suspended in water and methanol, the latter used as a sacrificial agent. The water suspension was placed inside a sealed quartz batch photoreactor under constant stirring and and illuminated by a 250W mercury lamp for 8 h with gas evoultion being monitored by gas chromatography (GC). Preeliminary results indicate that the employed synthesis method was effective to obtain the required crystalline phase. However, optimal conditions are needed to decrease particle size and increase the tungstates surface areas. The bandgap energy of these tungstates was found to be within the visible light spectrum with a variation between 2.24 eV for CoWO4 to 2.56 eV for MnWO4, respetively. Maximum hydrogen production was achieved by sample MnWO4 with 139 μmH2/gcat, while the lowest production was observed for sample CoWO4 with 24 μmH2/gcat. From these preeliminary results it can be infered that simple and mixed metal transition tungstates can be considerer as potential candidates, as photocatalysts for H2 production via the splitting of the water molecule under visible light irradiation. | |
| 2015 | |
| Memoria de congreso | |
| Inglés | |
| OTRAS | |
| Versión revisada | |
| submittedVersion - Versión revisada | |
| Aparece en las colecciones: | Artículos de Congresos |
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